Mastitis is an infectious disease of the bovine udder caused by harmful micro-organisms entering the teat canal through the teat orifice and/or through lesions upon the surface of bovine udder quarters. Usual sources of harmful microbes include the milker, unsanitary milking equipment, other mastitic cows, an unsanitary environment and the cow's own eliminations and secretions. Annual pecuniary loss to this disease has been estimated to be in the hundreds of millions of dollars in the United States alone. Estimates of total annual milk product lost in the United States due to mastitis range from 10 to 25 percent.
In 1916, Moak proposed the practice of dipping cow teats in a germicidal solution immediately after milking; however, this has become a well spread practice in the dairy industry only in the last decade. This time lag has been most unfortunate for there is ample documentation in scientific and trade journals attesting to the fact that a post-milking teat-dipping program will significantly reduce the number of cases of mastitis.
Teat-dipping using a well balanced formulation accomplishes these essential functions: (1) Dipping removes the final drop of milk on the end of the teat. Unattended, this drop of milk is an excellent breeding media for infectious organisms. (2) Dipping in an effective sanitizing solution controls most organisms on the skin, reducing the number that may enter the teat canal. Among the organisms that are controlled are those that have been shown to cause mastitis. (3) Dipping in a balanced formulation aids in healing minor skin lesions and contributes to the overall health of the udder.
While there are a number of germicides that are effective in preventing and treating mastitis, most preparations have the disadvantage of only remaining in contact with the udder for a short time due to the mobility of the preparation. Longer contact time is desirable in order to insure a higher kill rate for the harmful bacteria.
While proper application of many dipping preparations will kill the harmful bacteria on the udder at the time of dipping, the majority of the bacterial invasions of the udder probably occur during the intermilking period. A dip preparation that formed a protective pliable film about the teat would reduce its susceptibility to dirt, bacteria and other foreign matter. Such a film would also form a bacteriostatic barrier about the teat, reducing the possibility of bacterial invasion. Certain oil based preparations, such as those disclosed in U.S. Pat. No. 3,222,252 will upon drying form a protective coating that will remain on the udder for some time. However, Philpot and Pankey, in the Journal of Dairy Science, Vol. 58, pp. 205-216, have shown that oil-based teat dipping preparations perform poorly in preventing mastitis infections and were shown to frequently increase the numbers of mastitis producing organisms. Secondarily, oil based preparations are not easily removed by washing prior to milking. It is desirable that such preparations be completely removed prior to milking to prevent any contamination of the milk by the preparation.
Because it is essential that the udders of all the cows in the herd be dipped after milking, an easy method of determining whether the cows have been treated is desirable. Complexed iodines, commonly termed "iodophors" have been employed as germicides in teat-dipping solutions for over a decade. They offer the advantage of being chromophoric. It is highly desirable to obtain this characteristic with other germicides.